This report describes progress made from October 1, 1981 to September 30, 1983. During this period work proceeded on three main lines of study: 1) various aspects of visual motion perception, 2) collaborative work on contrast sensitivity and pilots' performance in aircraft simulators, and 3) individual differences in responses to temporal transients. The most extensive of the three work-units dealt with motion perception by human observers. The main findings include the following: 1) Perceived speed of a moving target varies with that target's contrast and retinal eccentricity. In particular, many targets undergo illusory slowing when they appear in the periphery in the visual field. 2) Detection of a moving target is often dissociated from the ability to identify the direction in which the target moves. In particular, the accuracy with which target direction can be judged, even for highly visible targets, seems to far less good than previously suspected. 3) Relatively small amounts of training can significantly improve an observer's ability to discriminate between two highly similar directions of target motion. Moreover, this effect is well-restricted to the training direction and other, similar directions; the training effect is retained without decrement for at least two months. The results suggest that this improvement with training represents a genuine change in visual function.

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